An organic light emitting device includes a light emitting layer made of an organic material, and has electrical properties similar to those of a diode. Such an organic light emitting device is a display based on the principle in that, when voltage is applied between a lower electrode and an upper electrode, between which a plurality of organic layers is formed, electrons and holes are injected from a cathode and an anode and then recombined in the organic layer to produce light.
An organic light emitting device is advantageous in terms of its wide viewing angle, ultra-high speed response and self-lighting characteristics, and may thus be utilized as any video display medium from a small size to a large size. Furthermore, because of low power consumption and no need for a backlight, such a device may be manufactured to be lightweight and slim and is very suitable for use in a flat panel display.
When the lower electrode is formed so as to possess good electrical properties and to be uniform and flat before formation of an organic film, which is a light emitting portion of the organic light emitting device, it is possible to manufacture an organic light emitting device having high efficiency without shorting of the device.
In an existing organic light emitting device, forming a lower electrode and an insulating film may be carried out by deposition and etching, and an organic layer and an upper electrode are formed using a vacuum process. Recently, however, a technique for manufacturing an organic light emitting device using a shadow mask has been developed, thus simplifying the manufacturing process.
However, the organic light emitting device using a shadow mask as recently developed is problematic because the surface of a transparent electrode on a substrate is not flat, and thereby leakage current of the organic light emitting device may occur and electrical properties of the device may deteriorate or shorting of the device may be caused.